Intra-articular tendon sling fixation screw

ABSTRACT

A fixation screw that secures a graft to a bone. The fixation screw is formed with a body member having a distal end, a proximal end, a central axis, and a cannula through the central axis of the body member. The body member also has a shank portion which is formed with an external screw thread, and a head portion rigidly coupled to the shank portion. The head portion is formed to mechanically couple with a driver and also to directly receive the graft which the fixation screw anchors.

This is a continuation of application Ser. No. 08/949,368, filed Oct.14, 1997, now U.S. Pat. No. 5,968,045, which is hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION

This invention relates to an anchoring device for use in reconstructingtorn ligament connections, such as the anterior cruciate ligament (ACL)in the knee. Specifically, this invention relates to an improvedfixation screw, called an intra-articular tendon sling fixation screw bythe inventor, which is formed as a unitary construct. The fixation screwhas a threaded shank portion that can be inserted into bone and a headportion formed with an eyelet through which a graft, such as anautograft, an allograft or a prosthetic ligament, can be looped.

The fixation screw of the present invention is particularly suited forreconstructive surgery in which the fixation screw is preferablyinserted completely into bone and directly receives the graft. As such,the present invention is particularly suited for ACL reconstruction andfor posterior cruciate ligament (PCL) reconstruction in the knee. It isto be noted that ACL reconstruction has become a common operation. Onthe other hand, PCL reconstruction surgery is performed much less oftenas significant knee function can be maintained without the benefit ofthe PCL. Thus, for illustrative purposes, this specification will focuson ACL reconstruction surgery to illustrate the use, function andbenefits of the present invention.

Reconstructive surgeries of the ACL date back as far as 1904. Since thattime, a variety of different methods and devices for aiding in thereconstruction of the ACL have been patented and described. Most moderntechniques utilize arthroscopic procedures to minimize the size of anyincisions made. U.S. Pat. No. 5,374,269, granted to Thomas D. Rosenbergon Dec. 20, 1994 (hereinafter referred to as Rosenberg '269) isillustrative of the prior art. Rosenberg '269 describes variations on anumber of common techniques of ACL reconstruction.

Rosenberg '269 specifically claims a method of forming a passageway in afemur at the knee joint. Its specification does not limit itself,however, to only describing this specific sub-procedure. Rosenberg '269describes two ACL reconstruction methods that use the patellar tendon asthe graft and one method that uses the semitendinosus tendon. Both thepatellar tendon and the semitendinosus tendon can be harvested from theindividual having the knee surgery and are, therefore, autografts. Thesetendons are commonly used as the replacement graft for the torn orruptured ACL. In each of the methods described in Rosenberg '269,tunnels are drilled in the tibia and the femur. These tunnels end in theintra-articular space of the joint at the attachment sites of the tornor ruptured ACL. The tunnel in the tibia goes from the tibial cortex ata site between 20 and 25 mm below the knee joint to the intra-articularspace of the knee joint. The tunnel in the femur is a closed-end tunnel,although it may be formed with a channel that extends to the lateralsurface of the femur, depending on the graft attachment method used.Rosenberg '269 modifies the prior art method of drilling the femoraltunnel, but is otherwise indicative of an accepted practice for formingthe femoral and tibial tunnels.

In Rosenberg '269, the graft, whether a patellar tendon or asemitendinosus tendon, is implanted with one end secured in theclosed-end femoral tunnel and the other end secured in the tibial tunnelor at a point adjacent to the tibial tunnel on the tibial cortex.

In the first method described by Rosenberg '269, using the patellartendon, the bone plug on the leading end of the graft can be locked inplace in the femoral tunnel with an interference screw. Rosenberg '269also teaches a method by which the leading end bone plug is attachedwith sutures that are anchored to the lateral femoral cortex by means ofa button. The sutures pass through a channel that extends from theclosed end of the femoral tunnel to the lateral surface of the femur.The sutures attach to the leading bone plug. In both methods using thepatellar tendon, the trailing bone plug is secured by staples to thetibial cortex below the tibial tunnel entrance.

Rosenberg '269 also describes a method for anchoring the semitendinosustendon. Elongated sutures are attached to the ends of the semitendinosustendon graft. The leading end of the graft is secured in a mannersimilar to the second method for securing the patellar tendon in thefemoral tunnel described above. That is by means of sutures attached toa button on the lateral femur cortex, which are passed through a channelto the end of the femoral tunnel where they attach to the semitendinosusgraft. The trailing edge of the graft is secured in the tibial tunnel bymeans of sutures that are affixed to a screw or post positioned on thetibia adjacent to the entrance of the tibial tunnel.

While the methods of preparing tunnels in the bones of the knee jointtaught by Rosenberg '269 are applicable to methods using the presentinvention, the present device differs materially from any device taughtin Rosenberg '269. The fixation screw of the present invention is ananchor. Rosenberg '269 teaches an interference screw. Furthermore, useof the fixation screw of the present invention requires vastly differingattachment methods for grafts than the methods taught by Rosenberg '269.First, the inventor prefers not to use the patellar tendon as a graftfor ACL reconstruction. Second, when the fixation screw of the presentinvention is used with the semitendinosus tendon, there is no need toform a channel from the closed-end tunnel in the femur to the surface ofthe femoral cortex, nor is there a need to make a lateral incision atthe lateral femoral cortex as is necessary with the method described byRosenberg '269. Thus, methods employing the present invention reduce thenumber of incisions made and trauma to the femur or other bone in whichthe fixation screw is inserted. They also do not require the use ofsutures for anchoring the leading end of the semitendinosus tendon inthe femoral tunnel.

While the present invention differs from the devices and methods taughtby Rosenberg '269 in both form and use, two endosteal ligament retainingdevices have been described that are more similar to the presentinvention in the methods by which they anchor a graft in the femur. Theyare U.S. Pat. No. 5,129,902, entitled “Endosteal Ligament Retainer,”granted to E. Marlowe Goble and Karl Somers on Jul. 14, 1992(hereinafter referred to as Goble '902) and U.S. Pat. No. 5,152,790,entitled “Ligament Reconstruction Graft Anchor Apparatus,” granted toThomas D. Rosenberg, Gerard S. Carlozzi and William J. Reimels on Oct.6, 1992 (hereinafter referred to as Rosenberg '790). Like the presentinvention, these inventions teach an anchor inserted into a closed-endfemoral tunnel that receives a graft. Also like the present invention,both of these devices are used in methods where the closed-end femoraltunnel is formed in the femur in a fashion similar to Rosenberg '269.However, like the method for which the present invention is designed andunlike Rosenberg '269, these methods and devices do not need a channelformed in the femur that passes from the closed-end tunnel to thelateral femoral cortex. Goble '902 teaches an anchor consisting of abasket or disk for receiving a graft which is rotatably attached to ascrew. The graft receiving disk or basket is able to spin on the screwhead, preventing the graft from twisting or rotating as the screw isdriven into the closed end of the femoral tunnel. The graft can eitherbe looped through an opening in the basket or sutured to the basket.

Rosenberg '790 also teaches an anchor assembly consisting of a basket,called a ring in this case, for receiving the graft which is rotatablyattached to a threaded body member. Like Goble '902, the graft receivingbasket is able to spin on the threaded body member. Rosenberg '790,however, teaches suturing the graft to the ring.

There are a number of material differences between the prior art and thepresent invention. Both Goble '902 and Rosenberg '790 aremulti-component anchors having moving parts. This can lead tocomplications. Furthermore, because the diameter of the basket of Goble'902 is much larger than the threads of the fixation screw, it couldbecome wedged against the edge or side of the femoral tunnel duringinstallation, making it difficult to fully insert or retrieve theanchor. It is to be noted that both Goble '902 and Rosenberg '790 teachusing sutures as an intermediate means for attaching the graft to theanchor. The sutures are the weak link in the attachment and suturebreakage is a consideration. Also, neither of the prior art devices arecannulated for use with a guide drill. Finally, in both Goble '902 andRosenberg '790, because the means for attachment of the graft arelocated away from the central axis of the anchor or threaded member, thegraft cannot be aligned with the axis of the anchor member, eitherduring or after installation.

Furthermore, in Goble '902, when sutures are not used to attach thegraft to the basket, the graft can end up being pinched between thebasket and the wall of the femoral tunnel. This is because the graft orgrafts must loop through openings in the arcuate walls of the basket onits periphery.

To summarize, the present invention provides a fixation screw that hasno moving parts, that can be installed in a closed-end femoral tunnelwith the use of a guide drill, receive a graft without the necessity ofsutures, receive a graft without causing pinching of the graft betweenthe fixation screw and the wall of the femoral tunnel, and that allowsthe anchored graft to be aligned with the central axis of the fixationscrew.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a fixation screw forattaching a graft to bone that is of unitary construction.

It is another object of the present invention to provide a fixationscrew that can be used with a guide drill.

It is a further object to provide a fixation screw that is self-tappingin bone.

It is a further object of the present invention to provide a fixationscrew that can receive a graft ligament without requiring the use ofsutures or other additional connective members.

Another object of the present invention is to provide a fixation screwthat can directly receive a graft ligament without pinching the graftbetween the wall of the tunnel and the head portion of the fixationscrew.

A further object of the present invention is to provide a fixation screwthat can receive a graft that is aligned with the central axis of thefixation screw.

Another object of the present invention is to provide a method ofattaching the graft to the fixation screw that allows the graft to bedoubled-over, forming a sling thereby increasing the tensile strength ofthe graft.

Another object of the present invention is to provide a fixation screwthat is suitable for anchoring a graft in the femur for reconstructingthe anterior cruciate ligament (ACL) of the knee.

A further object of the present invention is to provide a fixation screwthat is suitable for arthroscopic ACL reconstruction procedures.

Another object of the present invention is to provide a fixation screwthat is suitable to ACL reconstruction procedures that are minimallyinvasive so as to lessen trauma and facilitate patient rehabilitation.

Another object of the present invention is to provide a fixation screwthat is particularly suited for use with either the semitendinosustendon or the gracilis tendons, or both as the graft to be anchored inACL reconstruction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic anterior view of the left knee in flexion.Portions of the femur, tibia and fibula are shown with a tibial tunneland a closed end, femoral, endosteal tunnel having been drilled in thetibia and femur respectively. The knee is shown with a guide drill inplace, passing through the tibial tunnel and the femoral endostealtunnel for receiving the fixation screw of the present invention.

FIG. 2 is a schematic anterior view of the left knee in flexion. Adriver is shown inserted over the guide drill. The fixation screw of thepresent invention is attached to the driver and is partially insertedinto the closed end femoral tunnel. Two grafts are shown looped throughthe eyelet of the present invention. Sutures, attached to the ends ofthe grafts, pass through grooves on the driver handle and are tied at abutton on the end of the driver.

FIG. 3 is a schematic cross section of a knee in flexion. Portions ofthe femur and tibia are shown. The fixation screw is shown placed in thefemur. Two grafts are received by the eyelet of the fixation screw. Thetwo grafts are shown attached to the tibia cortical surface with bonestaples near the entrance of the tibial tunnel.

FIG. 4 is a front view of the preferred form of the fixation screw ofthe present invention inserted over a guide drill. The fixation screw isshown with a cutting flute at its distal end. It is also shown withopenings in the proximal end of the body member and head portion thatreceive corresponding extensions on a matching driver.

FIG. 5 is a front view of the fixation screw of the present inventioninserted over a guide drill. The fixation screw is shown with openingsin the proximal end of the body member and head portion that receivecorresponding extensions on a matching driver.

FIG. 6 is a front view of a portion of the fixation screw of the presentinvention and a portion of a driver for inserting the fixation screw.The head portion and part of the shank portion of the fixation screw areshown. The fixation screw is shown with openings in the proximal end ofthe body member and head portion that receive corresponding extensionson the driver.

FIG. 7 is a top view of fixation screw of the present invention, showingthe head portion of body member, taken generally along line 7—7 of FIG.6.

FIG. 8 is a front view of a portion of another form of the fixationscrew of the present invention and a portion of a driver for insertingthe fixation screw. The head portion and part of the shank portion ofthe fixation screw are shown. The fixation screw is shown with a portionof the cannula in the proximal end of the body member shaped to closelyreceive a hexagonal driver.

FIG. 9 is a top view of the fixation screw of the present invention,showing the head portion of the body member, taken along line 9—9 ofFIG. 8.

FIG. 10A is a side view of a portion of another form of the fixationscrew of the present invention and a portion of a driver for insertingthe fixation screw. The head portion and part of the shank portion ofthe fixation screw are shown. A forked driver with two prongs is showninserted over the proximal end of the body member.

FIG. 10B is a front view of a portion of the fixation screw of thepresent invention and a portion of a driver for inserting the fixationscrew. The head portion and part of the shank portion of the fixationscrew are shown. A forked driver with two prongs is shown inserted overthe proximal end of the body member.

FIG. 11 is a top view of the fixation screw of the present invention,taken along line 11—11 of FIG. 10A. A portion of the forked driver isshown in cross-section.

FIG. 12 is a perspective view of a portion of the fixation screw of thepresent invention and a portion of a driver for inserting the fixationscrew. The head portion and part of the shank portion of the fixationscrew are shown. A forked driver having two prongs is shown.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

The present invention teaches a graft fixation screw for securing agraft 1 to a bone 2. As shown in FIG. 4, the body member 3 of thepresent invention has a distal end 4, a proximal end 5, a central axis 6and a cannula 7 through said central axis 6 of said body member 3. Thefixation screw is formed with a cannula 7 to allow the fixation screw tobe used with a guide drill 8 for ensuring anatomic placement of thefixation screw.

The body member 3 of the fixation screw of the present invention alsohas a shank portion 9 which is formed with an external screw thread 10,and a head portion 11 rigidly coupled to the shank portion 9. The headportion 11 is formed with means for mechanically coupling with a driverand also with means for securing the graft 1 to the head portion 11.

As is also shown in FIG. 4, in the preferred embodiment of the presentinvention, the cannula 7 in the shank portion 9 of the body member 3 isdimensioned to closely receive a guide drill 8.

In the preferred embodiment of the present invention, the thread 10 onthe shank portion 9 is self-tapping in cancellous bone. Also in thepreferred embodiment, the thread 10 starts substantially at the distalend 4 of the body member 3. As is shown in FIG. 4, the fixation screw ofthe present invention is preferably formed with one or more flutes 12 inthe shank portion 9 and thread 10 to improve the ability of the thread10 to tap into cancellous bone. As is also shown in FIG. 4, the thread10 extends from the distal end 4 of the body member 3 to better anchorthe fixation screw in bone 2.

As is shown in FIG. 3, in the preferred embodiment of the presentinvention the means for securing the graft 1 to the head portion 11 isan eyelet 13 formed in the head portion 11 that is large enough toreceive the graft 1. The graft 1 is looped or threaded through theeyelet 13. As is shown in FIG. 3, the graft 1 preferably consists of twoseparate members, specifically the gracilis tendon and thesemitendinosus tendon.

As is shown in FIG. 4, in the preferred embodiment of the presentinvention, the central axis 6 bisects the eyelet 13, such that when thegraft 1 consists of only one member, it can align with the central axis6. When two separate members are used for the graft 1, the position ofthe eyelet 13 in relation to the central axis 6 helps the separatemembers of the graft 1 to be positioned as closely as possible to thecentral axis 6 and away from the side wall 14 of the endosteal tunnel 15in which the fixation screw is being inserted. FIG. 3 shows aclosed-end, endosteal tunnel 15 formed in the femur 2 which forshort-hand purposes is called a femoral endosteal tunnel 15.

As is best shown in FIGS. 2 and 4, in the preferred embodiment of thepresent invention, the diameter of the eyelet 13 is larger than thewidth of the cannula 7 such that the cannula 7 can receive a guide drill8 for positioning the fixation screw at the same time that the graft 1is received by the eyelet 13.

As is best shown in FIG. 3, the eyelet is shaped so that the graft ismoved away from the side wall 14 of the endosteal tunnel 15 when it ispulled taut so as to prevent damage to the graft 1 due to abrasion withthe side wall 14 of the endosteal tunnel 15. This is accomplished byforming the eyelet 13 so that it approaches an ellipse or oval in shape.

In one embodiment of the present invention, the means for mechanicallycoupling with a driver consists of forming a portion of the cannula 7 inthe head portion 11 to closely receive and mechanically couple with acorresponding driver 16. As is shown in FIGS. 8 and 9, a portion of thecannula 7 in the head portion 11 is formed to closely receive andmechanically couple with a hexagonally shaped driver 16.

In another form of the present invention, the entire cannula 7 in thehead portion 11 can be formed to closely receive and mechanically couplewith a driver, such that the driver as well as the guide drill 8 passesthrough the eyelet 13. In such an embodiment, the diameter of the eyelet13 should be larger than the width of the cannula 7, such that thecannula 7 in the head portion 11 can receive a guide drill 8 forpositioning the fixation screw and a driver for inserting the fixationscrew at the same time that the graft 1 is received by the eyelet 13.

As is shown in FIGS. 10A , 10B, 11 and 12, in another form of thepresent invention the means for mechanically coupling with the drivercan consist of the proximal end 5 of the body member 3 formed to beclosely received between cooperating prongs 17 and 18 of a driver 19.

As is shown in FIGS. 4, 5, 6 and 7 in the preferred form of theinvention the means for mechanically coupling with the driver consistsof forming two bores 20 and 21 in the head portion 11 of the body member3 that can receive corresponding extensions 22 and 23 on a specialdriver 24. In the preferred form, the pair of bores 20 and 21 in thehead portion 11 are cylindrical and couple with a cannulated driver 24with corresponding cylindrical extensions 22 and 23. The preferred meansfor mechanically coupling with the driver allows the head portion 11 tobe formed so as to provide maximum room for the graft 1 to pass aroundthe proximal end 5.

In the preferred embodiment of the fixation screw, the minor diameter 25of the shank 9 will be approximately 30% of the major diameter 26 of thethread 10. The minor diameter 25 is minimized to lessen the displacementof cancellous bone when only a drill guide 8 is used to prepare the bone30 for the insertion of the threaded shank 9 past the closed end 27 ofthe endosteal tunnel 15.

The driver 16, 19, or 24 is preferably marked so that when the fixationscrew of the present invention is fully seated in the bone 2, a mark 28on the driver 16, 19, or 24 will align with the entrance of theendosteal tunnel 15.

The present invention can be formed of metal (e.g. 316 stainless steelor titanium), a non-absorbable polyethylene, an absorbable polylacticacid substance, or an absorbable polyglycolic acid substance to name afew bio-compatible substances.

With reference to FIGS. 1, 2 and 3, preferably, the intra-articulartendon sling fixation screw of the present invention is used inarthroscopic ACL reconstruction surgery in the following manner.

A tibial tunnel 29 is formed in the tibia 30 with its entrance at thetibial cortex 31 and its exit at the attachment site of the anteriorcruciate ligament on the tibia 30. A tibial guide is used to determinethe insertion point for the guide drill 8. The guide drill 8 is insertedinto and through the tibia 30 at the proper angle. Using the guide drill8 as a guide, a coring drill removes a section of the tibia 30 formingthe tibial tunnel 29. The bone section removed by the coring drill isused to create bone plugs which are inserted into the tibial tunnel 29and the femoral endosteal tunnel 15 at the end of the procedure.

Next the location of the closed-end endosteal tunnel 15 in the femur 2is determined. The endosteal tunnel 15 is to be formed in the femur 2with its entrance at the attachment point of the anterior cruciateligament with the femur 2. This tunnel is also known as a femoralendosteal tunnel 15. A femoral tunnel guide is used to determine thecorrect angle and point of entry for the endosteal tunnel 15 into thefemur 2. A guide drill 8 is then drilled into the femur 2 in the correctanatomic position—the insertion point of the ACL in the femur 2—usingthe femoral tunnel guide as a pilot. The guide drill 8 serves to markthe anatomic position for subsequent boring. The guide drill 8 ispreferably drilled into the femur 2 deep enough to engage the anteriorlateral femoral cortex 32. This prevents the guide drill 8 from backingout. The guide drill 8 also passes through the tibial tunnel 29.

The femoral endosteal tunnel 15 is then formed using a cannulated acorndrill that fits over the guide drill 8. The femoral endosteal tunnel 15should be drilled 1 mm larger than the major diameter 26 of the thread10, so as to facilitate insertion of the fixation screw into theclosed-end, endosteal tunnel 15. The appropriately sized acorn drill isthus 1 mm larger than major diameter 26 of the thread 10 of the fixationscrew. The femoral endosteal tunnel 15 should be drilled deep enough tocompletely receive the head portion 11 of the fixation screw and a boneplug when the threaded shank 9 of the fixation screw has been completelyinserted into the femur 2.

The acorn drill is then removed. The intra-articular tendon slingfixation screw of the present invention is then prepared. The graft 1 islooped through the eyelet 13 of the fixation screw. In the preferredembodiment, the graft 1 consists of both the semitendinosus and gracilistendons for added strength. The fixation screw is then inserted over thedrill guide 8, with the semitendinosus tendon looped through the eyelet13 on one side of the drill guide 8 and the gracilis tendon loopedthrough the eyelet 13 on the other sided of the drill guide 8.

Next the preferred driver 24 is inserted over the drill guide 8 andreleasably attached to the fixation screw. In the preferred embodimentof the fixation screw, a pair of cylindrical bores 20 and 21, formed inthe head portion 11, couple with corresponding cylindrical extensions 22and 23 on the cannulated driver 24. Prior to threading the graft 1 intothe eyelet 13 of the fixation screw, sutures 33 are attached to the endsof the grafts 1. These sutured ends of the grafts 1 are then pulledtaut, with the attached sutures 33 fitting into grooves 34 on the sidesof the handle 35 of the driver 24. The sutures 33 are tied off on abutton 36 on the driver 24. Pulling the grafts 1 taut causes them tomove away from the side wall 14 of the femoral endosteal tunnel 15 sothey cannot be abraded. With the sutures 33 tied off on the button 36and nestled in the grooves 34 of the driver handle 35, the grafts 1 willturn with the driver 24 and not twist.

The fixation screw is then inserted into the femoral endosteal tunnel15. When the distal end 4 of the fixation screw touches the closed end27 of the femoral endosteal tunnel 15, the surgeon begins to drive thefixation screw into the femur 2 by rotating the driver 24 and applyingpressure. The surgeon can tell when the fixation screw has been driveninto the bone 2 to a sufficient depth by referring to markings 28 on thedriver 24 which will align with the entrance of the femoral endostealtunnel 15 when the fixation screw is fully seated in the bone 2.

When the fixation screw is in place, the sutures 33 attached to the endsof the grafts 1 are removed from the driver 24. Then the driver 24 andthe drill guide 8 are removed. The grafts 1 are pulled taut and fixed tothe tibial cortex 31 near the entrance of the tibial tunnel 29 by meansof staples 37 in a pants-over-vest attachment system. Then the sutures33 are cut at the ends of the grafts 1.

The bone plugs fashioned from the tibial bone section removed by thecoring drill are then placed in the femoral endosteal tunnel 15 and thetibial tunnel 29 to allow bone to tendon healing.

If a self-tapping form of the fixation screw is not used, then a stepmust be added. After the femoral endosteal tunnel 15 is formed with theacorn drill. A tap must be used to pre-cut a path in the cancellous boneat the closed end 27 of the femoral endosteal tunnel 15 for the threadedshank portion 9 of the fixation screw.

The invention is not limited to the specific form shown, but includesall forms within the definitions of the following claims.

I claim:
 1. A ligament reconstruction graft fixation screw for securinga graft to a bone having a tunnel formed therein comprising: a. a bodymember, having a distal end, a proximal end, a central axis and acannula through said central axis of said body member; b. a shankportion, having an external screw thread; and c. a head portion rigidlyand fixedly coupled to said shank portion so that said head portionmoves in unison with said shank portion, said head portion being formedwith means for mechanically coupling with a driver and with an openingfor securing said graft to said head portion, wherein said cannulapasses through said opening and said opening is large enough to receivesaid graft.
 2. The fixation screw of claim 1, wherein: said cannula insaid shank portion of said body member is dimensioned to closely receivea guide drill.
 3. The fixation screw of claim 1, wherein: said thread isself-tapping in cancellous bone.
 4. The fixation screw of claim 3,wherein: a flute is formed in said shank portion of said body member. 5.The fixation screw of claim 1, wherein: said thread extends from saiddistal end of said body member.
 6. The fixation screw of claim 5,wherein: said thread is self-tapping in cancellous bone.
 7. The fixationscrew of claim 6, wherein: a flute is formed in said shank portion ofsaid body member.
 8. The fixation screw of claim 7, wherein: saidcentral axis bisects said opening, such that said graft can align withsaid central axis.
 9. The fixation screw of claim 8, wherein: thediameter of said opening is larger than the width of said cannula suchthat said cannula can receive a guide drill for positioning saidfixation screw at the same time that said graft is received by saidopening.
 10. The fixation screw of claim 1 wherein: said means formechanically coupling with said driver consists of a portion of saidcannula in said head portion formed to closely receive and mechanicallycouple with said driver.
 11. The fixation screw of claim 1, wherein: a.said means for mechanically coupling with said driver consists of saidcannula in said head portion formed to closely receive and mechanicallycouple with said driver; and b. said opening for securing said graft tosaid head portion is large enough to receive said graft, and thediameter of said opening is larger than the width of said cannula suchthat said cannula in said head portion can receive a guide drill forpositioning said fixation screw and a driver for inserting said fixationscrew at the same time that said graft is received by said opening. 12.The fixation screw of claim 1 wherein: said means for mechanicallycoupling with said driver consists of said proximal end of said bodymember formed to be closely received between cooperating prongs on saiddriver.
 13. The fixation screw of claim 1 wherein: said means formechanically coupling with said driver consists of at least two boresformed in said head portion of said body member that can receivecorresponding extensions on said driver.
 14. The fixation screw of claim1 wherein: said cannula in said shank portion of said body member isdimensioned to closely receive a guide drill.
 15. The fixation screw ofclaim 14, wherein: said central axis bisects said opening, such thatsaid graft can be bisected by said central axis. 16.The fixation screwof claim 15, wherein: said thread is self-tapping in cancellous bone.17. A ligament reconstruction graft fixation screw and graft assemblyfor securing a graft to a bone having a tunnel formed thereincomprising: a. a body member, having a distal end, a proximal end, acentral axis and a cannula through said central axis of said bodymember; b. a shank portion, having an external screw thread; and c. ahead portion rigidly and fixedly coupled to said shank portion so thatsaid head portion moves in unison with said shank portion, said headportion being formed with means for mechanically coupling with a driverand with an opening for securing said graft to said head portion; and d.a graft directly secured to said head portion of said body member, bylooping said graft through said opening.